Microbial Cell Factories最新文献

{"title":"Increasing lipid accumulation in Chlamydomonas by serial knocking out of DYRKP1 kinase and ADP-glucose pyrophosphorylase.","authors":"Minjae Kim, Ji Yeon Kim, Kyong Ha Han, Hyeon Ho Shin, EonSeon Jin","doi":"10.1186/s12934-025-02824-8","DOIUrl":"https://doi.org/10.1186/s12934-025-02824-8","url":null,"abstract":"<p><p>Microalgae are promising sustainable feedstocks for biodiesel production. Among the primary carbon reservoirs in microalgae, starch and lipids are the main targets for metabolic engineering aimed at enhancing productivity. Redirecting carbon flux from starch toward lipid biosynthesis has been considered an effective strategy to improve lipid yield, and manipulating upstream regulators may allow broader control over metabolic networks. DYRKP1, a plant-specific dual-specificity tyrosine-phosphorylation-regulated kinase conserved in photosynthetic eukaryotes, has been implicated in regulating intracellular carbon partitioning. In this study, we investigated the physiological and metabolic effects of DYRKP1 deficiency in a cell-wall-less strain of Chlamydomonas reinhardtii. To further enhance lipid accumulation, we additionally knocked out ADP-glucose pyrophosphorylase (AGP), a key enzyme involved in starch biosynthesis. The total fatty acid content of DYRKP1-AGP double knockout (dKO) mutants was higher than that of their parental strain (CC4349) under both nitrogen-replete and deplete conditions, and was even 1.2-fold higher than that of the AGP single knockout (agp) mutant under nitrogen-deplete conditions. The DYRKP1 single knockout mutants exhibited fatty acid composition similar to the parental strain, regardless of nitrogen depletion. The fatty acid composition of the dKO mutants resembled that of the agp mutant under nitrogen-replete conditions, but diverged upon nitrogen starvation, suggesting a conditional interaction between upstream regulation and metabolic flux. This finding implies that disrupting upstream regulators like DYRKP1 may offer limited additional benefit when key downstream bottlenecks, such as starch biosynthesis, are already removed. Overall, our study underscores the layered complexity of carbon partitioning in C. reinhardtii and the importance of context-dependent metabolic regulation in optimizing lipid production.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"194"},"PeriodicalIF":4.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12372370/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144961099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulation of the Ald gene encoding alanine dehydrogenase and its induction of ammonium-tolerant nitrogen fixation in Paenibacillus polymyxa WLY78.","authors":"Haowei Zhang, Yuxing Han, Hui Tan, Qin Li, Sanfeng Chen","doi":"10.1186/s12934-025-02823-9","DOIUrl":"https://doi.org/10.1186/s12934-025-02823-9","url":null,"abstract":"<p><strong>Background: </strong>Paenibacillus polymyxa WLY78, a Gram-positive diazotroph with plant growth promotion and phytopathogen suppression, represents a promising candidate for agricultural biofertilizers. However, its nitrogen fixation capacity is inherently limited by ammonium-mediated repression. Recent studies revealed that ammonium-tolerant nitrogen fixation in certain Paenibacillus species correlates with alanine overproduction mediated by alanine dehydrogenase (ADH) encoded by the ald gene.</p><p><strong>Results: </strong>This study establishes a dual regulatory mechanism governing ald expression in P. polymyxa WLY78. The transcription activator AdeR positively regulates ald expression, while the global nitrogen regulator GlnR exerts repression on both ald and its activator gene adeR. Under high ammonium conditions, GlnR-mediated suppression maintains basal ald expression levels, preventing alanine biosynthesis. Upregulation of ald expression through high-copy plasmid or mutagenesis of GlnR-binding sites in the adeR-ald regulatory region significantly enhanced alanine concentration. Both endogenous overproduction and exogenous supplementation of alanine suppressed glutamine synthetase (GS) activity, thereby reducing intracellular glutamine levels. This prevents the formation of glutamine-feedback-inhibited GS complexes (FBI-GS), disrupting the GlnR-FBI-GS interaction required for nif gene repression. Consequently, GlnR transitions to its activated state, enabling nif gene expression even under elevated ammonium concentrations.</p><p><strong>Conclusions: </strong>Our findings elucidate a conserved regulatory paradigm in Paenibacillus species where alanine metabolism modulates nitrogen fixation through GS-mediated metabolic signaling. The ald overexpression or exogenous alanine supplementation can bypass ammonium inhibition provides practical strategies for enhancing biofertilizer performance in nitrogen-rich agricultural soils.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"193"},"PeriodicalIF":4.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12369066/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144961026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying new targets for improving terpenoid biosynthesis in Yarrowia lipolytica through random genomic cytosine base editing.","authors":"Zhenxia Li, Bo Liu, Rongtao Lv, Zhe Sun, QingYan Li, XueLi Zhang","doi":"10.1186/s12934-025-02819-5","DOIUrl":"10.1186/s12934-025-02819-5","url":null,"abstract":"<p><strong>Background: </strong>Genome-scale mutagenesis integrated with high-throughput phenotypic screening and causal mutation mapping serves as a robust paradigm for systemic genetic dissection. Despite the application of non-homologous end joining (NHEJ)-mediated genome editing in Yarrowia lipolytica, the development of alternative genome-wide mutagenesis strategies remains unexplored in this industrially relevant oleaginous yeast.</p><p><strong>Results: </strong>We developed the Helicase-Assisted (Helicase-CDA) system, a genome-wide mutagenesis platform integrating the helicase domain of Yarrowia MCM5 (Encoded by YALI1_A01766g) with cytidine deaminase (CDA). This system enables continuous C-to-T specific mutations at random genomic loci. Applied to an industrial β-carotene-producing Y. lipolytica strain, Helicase-CDA system generated a mutagenized library through 7-day subculturing. Through high-throughput screening, we successfully isolated the mutant strain CDA-14, which demonstrated a 25% enhancement in β-carotene production (448.1 mg/L) compared to the wild-type strain. Notably, its productivity of β-carotene reached 6.15 g/L in fed-batch fermentation. Whole-genome sequencing revealed a G1637A substitution in YALI1_B16239g, which encodes a membrane protein showing homology to sterol biosynthesis regulator MGA2. This mutation led to reduced ERG1 expression level and redirected central carbon flux toward carotenoid synthesis by perturbing isoprenoid precursor partitioning.</p><p><strong>Conclusion: </strong>Helicase-CDA system circumvents the dependency on NHEJ-mediated whole-genome mutation approach, offering a robust tool for continuous genome evolution in pre-engineered industrial strains. This study not only enhances genome editing in Y. lipolytica but also identifies a practical target for optimizing terpenoid biosynthesis, demonstrating significant potential for applications in metabolic engineering and synthetic biology.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"192"},"PeriodicalIF":4.9,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12366007/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144883183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PRMT5 promotes cellulase production by regulating the expression of cellulase gene eg2 through histone methylation in Ganoderma lucidum.","authors":"Yefan Li, Zi Wang, Zhouyu Li, Xin Tang, Tianyu Ji, Rui Liu, Mingwen Zhao","doi":"10.1186/s12934-025-02814-w","DOIUrl":"10.1186/s12934-025-02814-w","url":null,"abstract":"<p><strong>Background: </strong>Cellulase can degrade cellulose into reducing sugar, participating in the natural carbon cycle. Simultaneously, cellulase enhances the efficiency and quality of industrial production while also demonstrating significant potential in environmental protection and bioenergy development. Ganoderma lucidum, as a white rot fungus, secret a large amount of cellulase during growth. It is reported that some post-translational modification affects cellulase production. Protein arginine methyltransferase 5 (PRMT5) is involved in transcriptional regulation, RNA processing and signal transduction of biological processes. Therefore, this study primarily investigated whether and how PRMT5 was involved in the regulation of cellulase production in G. lucidum.</p><p><strong>Results: </strong>Our study found that silencing prmt5 reduced the activity of cellulase by 23%, and the growth rate of G. lucidum mycelium in wood chip tube by approximately 71%. The degradation of agricultural waste corn straw and corn cob decreased by approximately 60% and 51%, respectively. These results suggest that PRMT5 may promote cellulase production in G. lucidum. Through ChIP-qPCR, we found that PRMT5 could positively regulate the expression of endoglucanase 2 (eg2) through histone methylation, and further study on the construction of eg2 silencing and overexpression strains showed that the expression of eg2 promoted cellulase activity.</p><p><strong>Conclusions: </strong>Taken together, our results suggest that PRMT5 in G. lucidum promotes cellulase production by regulating the expression of cellulase gene eg2 through histone methylation.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"191"},"PeriodicalIF":4.9,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12363083/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144883185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Green synthesis of silver nanoparticles (AgNPs) from G. stearothermophilus GF16: stable and versatile nanomaterials with antioxidant, antimicrobial, and catalytic properties.","authors":"Alessia Di Fraia, Giovanni Dal Poggetto, Michela Salamone, Federica Carraturo, Patrizia Contursi, Marco Guida, Danila Limauro, Viviana Scognamiglio, Manuela Rossi, Gabriella Fiorentino","doi":"10.1186/s12934-025-02815-9","DOIUrl":"10.1186/s12934-025-02815-9","url":null,"abstract":"<p><strong>Background: </strong>Silver nanoparticles (AgNPs) have attracted considerable interest for their distinctive physicochemical properties and wide-ranging applications in nanomedicine, environmental catalysis, and antimicrobial applications. However, sustainable and robust biosynthesis methods remain a challenge.</p><p><strong>Results: </strong>In this study, we report the biosynthesis of thermostable AgNPs using the secretome of Geobacillus stearothermophilus GF16, a thermophilic and metal-resistant bacterium isolated from the hydrothermal volcanic area of Pisciarelli, Italy. The synthesis was performed without specialized growth media, relying solely on the cell-free bacterial supernatant, and was systematically optimized by varying precursor concentration, temperature, pH, and reaction time. The nanoparticles were characterized by UV-Vis spectroscopy, dynamic light scattering, Fourier-transform infrared spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy. Morphological analysis showed predominantly subspherical nanoparticles with average diameters of 17 ± 5 nm (SEM) and 16 ± 5-7 nm (TEM), depending on precursor concentration. Thermogravimetric analysis demonstrated excellent thermal stability with retention of structural integrity up to 120 °C, an exceptional feature among biogenic AgNPs. The obtained AgNPs exhibited remarkable radical scavenging activity, reaching up to 79% in DPPH and 75% in ABTS assays at 100 µg/mL, highlighting a level of antioxidant performance rarely observed in AgNPs of bacterial origin. In addition to their redox properties, the nanoparticles demonstrated efficient catalytic activity as evidenced by the complete degradation of Congo Red in 20 min and 4-nitrophenol in 35 min. Time-kill assays and minimum inhibitory concentration (MIC) also showed a broad-spectrum antimicrobial potential with complete inhibition of Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella Typhimurium at 100 µg/mL. Interestingly, MIC values were significantly lower than those reported for comparable AgNPs. Notably, the nanoparticles also displayed hemocompatibility, validated by hemolysis assays performed on both healthy and β-thalassemic erythrocytes, with hemolysis rates consistently below the 2% safety threshold.</p><p><strong>Conclusions: </strong>Overall, this study presents the first comprehensive characterization of AgNPs biosynthesized by a thermophilic bacterium, highlighting their multifunctional potential. The use of a thermophilic bacterium as a robust and flexible microbial nanofactory offers a novel eco-friendly and scalable strategy for AgNP production. The resulting nanoparticles exhibit unique thermal stability, broad-spectrum bioactivity, and clinically relevant hemocompatibility, underscoring their promising applicability in nanomedicine, green catalysis, and environmental remediation.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"189"},"PeriodicalIF":4.9,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12362984/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144883182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving nutritional quality and aflatoxin detoxification of peanut meal by co-fermentation with Weizmannia coagulans, Bacillus subtilis, and supplemented enzymes.","authors":"Youwei Chen, Hao Huang, Dan Li, Limei Zou, Wendi Yu, Weiwei Dong, Xiang Yu, Yanli Feng, Jun Liu, Shumiao Zhao, Yunxiang Liang, Yuanliang Hu, Nan Peng","doi":"10.1186/s12934-025-02816-8","DOIUrl":"10.1186/s12934-025-02816-8","url":null,"abstract":"<p><strong>Background: </strong>Peanut meal, a high-protein agricultural by-product, faces challenges as animal feed due to anti-nutritional factors, poor protein digestibility, aflatoxin contamination, and imbalanced amino acids. Microbial fermentation is one of the most effective methods to reduce anti-nutritional factors and enhance the nutritional value of peanut meal. Compared to single-strain fermentation, microbial-enzyme co-fermentation exhibits enhanced degradation efficiency, accelerates nutrient release, improves product safety by reducing mycotoxins and anti-nutritional factors, enhances sensory properties, and increases fermentation consistency and stability. However, research on microbial-enzyme co-fermentation of peanut meal remains limited, particularly regarding the co-fermentation of Weizmannia coagulans and Bacillus subtilis with enzyme preparations, which has yet to be systematically investigated. Therefore, this study aims to evaluate and optimize the use of Weizmannia coagulans for microbial-enzyme co-fermentation to enhance the nutritional quality and reduce anti-nutritional factors in peanut meal.</p><p><strong>Results: </strong>Peanut meal fermentation with Weizmannia coagulans BC01, Bacillus subtilis BS27, and the synergistic enzyme system (acid protease and hemicellulose) was optimized through single factor experiments and response surface methodology. This process led to significant reductions in crude fiber (from 7.05 to 2.88%) and anti-nutritional factors, with trypsin inhibitors decreasing from 0.30 to 0.03% and phytic acid from 1.43 to 0.35%. Aflatoxin B1 was reduced from 43.87 µg/kg to 6.20 µg/kg. Nutritional quality improved markedly, with flavonoid content increasing from 1.2 to 3.01%, reducing sugars increasing from 0.7 to 7.02%, and total acids increasing from 1.65 to 5.92%. Protein composition and digestibility were markedly improved, with crude protein, acid-soluble protein, and small peptide contents increasing by 18.2%, 546%, and 447%, respectively. Additionally, the degree of protein hydrolysis and in vitro digestibility rose to 40.77% and 68.91%, respectively. Total amino acid content increased by 14.3%, contributing to a more balanced amino acid profile.</p><p><strong>Conclusion: </strong>The study indicates that microbial-enzyme co-fermentation involving W. coagulans effectively reduces anti-nutritional factors in peanut meal while enhancing its nutritional value. These findings provide a sustainable approach to transforming peanut meal into high-value animal feed, offering a practical solution to address the protein feed supply gap. Further validation via animal trials is necessary to evaluate its efficacy as a replacement for conventional protein feed sources.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"190"},"PeriodicalIF":4.9,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12362912/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144883184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time pH and temperature monitoring in solid-state fermentation reveals culture physiology and optimizes enzyme harvesting for tailored applications.","authors":"Md Fauzul Kabir, Afranul Qader Ovi, Lu-Kwang Ju","doi":"10.1186/s12934-025-02820-y","DOIUrl":"10.1186/s12934-025-02820-y","url":null,"abstract":"<p><p>Enzyme production is crucial for biorefinery applications and the valorization of agricultural residues. However, real-time monitoring of pH and temperature in enzyme-producing solid-state fermentation (SSF) is generally regarded as challenging due to the system's complexity, with previous studies relying primarily on sacrificial sampling for pH measurements. This study integrates real-time monitoring of pH and temperature with systematic nutrient medium optimization to enhance the SSF enzyme production of α-galactosidase, invertase, pectinase, xylanase, and cellulase by Aspergillus niger NRRL 322 using soybean hulls as the sole carbon source. By capturing dynamic shifts in pH and temperature throughout fermentation, this approach provided important insights into cell growth dynamics, metabolic transitions, and their direct correlations with enzyme production profiles. Comparative analysis of different nutrient media, including nitrogen sources, macronutrient concentrations, and medium strengths, revealed that nitrogen supplementation and balanced macronutrient levels are critical for maximizing enzyme yields. Notably, pH fluctuations were strongly linked to enzyme activity trends, with pectinase and xylanase exhibiting distinct declines after reaching peak levels. The ability to monitor pH and temperature in real time enabled precise optimization of harvest timing for specific enzyme compositions tailored to different industrial applications. These findings establish real-time pH and temperature tracking as a valuable tool for improving SSF process control, paving the way for more efficient and economically viable enzyme production in sustainable biorefineries.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"188"},"PeriodicalIF":4.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12359996/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144874145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coating silicon catheters with the optimized and stable carotenoid bioproduct from Micrococcus luteus inhibited the biofilm formation by multidrug-resistant Enterococcus faecalis via downregulation of GelE gene expression.","authors":"Khaled B Al-Monofy, Ahmed A Abdelaziz, Amal M Abo-Kamar, Lamiaa A Al-Madboly, Mahmoud H Farghali","doi":"10.1186/s12934-025-02808-8","DOIUrl":"10.1186/s12934-025-02808-8","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Microbial carotenoids have gained industry interest due to their safety and diverse biological activities; however, the low yield of carotenoids hinders their applications. Hence, this study focused on optimizing carotenoid pigment production from Micrococcus luteus strains by studying 54 physical and chemical independent conditions. The chronic infections by Enterococcus faecalis are related to its ability to form biofilms on the surface of several implanted medical devices, such as urinary catheters. Therefore, the potential antibacterial and antibiofilm activities of the purified pigment against E. faecalis were investigated in our study.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Using one-factor-at-a-time experiments, the top-examined parameters were tryptic soya broth (TSB), agitation, temperature, pH, incubation time, inoculum size (IS), sodium chloride, tryptophan, glycerol, tryptone, glutaric acid, toluene, ferric sulphate, and disodium hydrogen phosphate. The data from the Plackett-Burman design showed that temperature, sodium chloride, tryptophan, and toluene were fundamental factors controlling carotenoid production. The conditions for the upstream process were determined via response surface methodology design, which included TSB medium, agitation speed of 120 rpm, temperature of 32.5 °C, pH = 7, incubation time of 96 h, 2% IS, sodium chloride (12.5 g/l), tryptophan (12.5 g/l), glutaric acid (5 g/l), toluene (12.5%), and disodium hydrogen phosphate (5 g/l). Submerged fermentation model validation using the M6 isolate (accession number of PP197163) revealed an increase in carotenoid production up to 6-fold (1.2 g/l). The produced pigment was purified and characterized as β-carotene, and the stability study showed that the extracted β-carotene was stable for a year in dimethyl sulfoxide at 4 °C. The MTT test data proved that the pigment was safe on human dermal fibroblasts with an IC&lt;sub&gt;50&lt;/sub&gt; equal to 542.7 µg/ml. For the first time, it was reported that the stable purified β-carotene exhibited powerful antibacterial activity against multidrug-resistant (MDR) E. faecalis, with inhibition zones ranging from 13 to 32 mm and minimum inhibitory concentrations (MICs) ranging from 3.75 to 30 µg/ml at safe concentrations. In addition, it was found that our stable purified β-carotene showed up to 94% inhibition in biofilm formation by strong biofilm-forming E. faecalis. In addition, the β-carotene-coated catheter manifested a lower biofilm formation by E. faecalis by up to 75.3%. Moreover, crystal violet staining, dual staining, and fluorescence staining techniques displayed immature biofilms of E. faecalis when treated with 0.25 and 0.5 MICs of β-carotene. The mechanistic pathway for the purified β-carotene's antibiofilm activity was strongly linked to the inhibition of gelatinase enzyme production (up to 100% inhibition) as manifested phenotypically, genotypically, and by molecular docking.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: ","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"186"},"PeriodicalIF":4.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12359931/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144874032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Green starch nanoparticles production in situ using α-amylase from a newly isolated Bacillus subtilis strain-MA6: statistical designs and characterizations.","authors":"Mohamed S Hasanin, Mohamed A A Abdella","doi":"10.1186/s12934-025-02812-y","DOIUrl":"10.1186/s12934-025-02812-y","url":null,"abstract":"<p><strong>Background: </strong>Starch is a carbohydrate polymer, made up of multiple glucose units, connected through glycosidic bonds. Starch nanoparticles (StNPs) are characterized as particles that possess at least one dimension measuring less than 1000 nm, while still being larger than a single molecule, and they have several uses in diverse technological fields. Various studies indicate that synthesizing StNPs through physical and chemical techniques is expensive, requires a lot of energy, and may harm human health and the environment. In contrast, the enzymatic synthesis of StNPs exerts milder impacts on the final products, rendering them more eco-friendly, safe, and healthier. So, amylases can produce StNPs with enhanced solubility, gelation, and viscosity characteristics by hydrolyzing soluble starches.</p><p><strong>Results: </strong>This study explores the production of starch nanoparticles (StNPs) by α-amylase enzyme in situ from a newly isolated bacterial strain, which was biochemically described, genetically identified, and deposited into the database of GenBank under the designation Bacillus subtilis strain-MA6 (accession number: ON840082). The production medium was adjusted by employing statistical optimization of several parameters using the Plackett-Burman design (P-BD) and Box-Behnken design (B-BD) of the response surface methodology (RSM). Optimization of medium parameters using P-BD and B-BD models caused a 14.5-fold increase in α-amylase production. The StNPs were synthesized from bulk starch using three different α-amylase activities. Based on the B-BD results, trial 5 (B-BD/T₅), trial 7 (B-BD/T₇), and trial 13 (B-BD/T₁₃) were selected for the StNPs characterization using Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and high-resolution transmission electron microscopy (HR-TEM) analysis. Trial 13 represented the highest α-amylase activity and observed high stability with an average zeta potential of about - 15.1 ± 3.2 mV. Moreover, HR-TEM showed the StNPs as spheres with an average size of about 43 nm.</p><p><strong>Conclusion: </strong>StNPs were synthesized from bulk starch using the B. subtilis strain-MA6 α-amylase enzyme. The concentration of α-amylase plays a role in converting bulk starch to nanosized particles, which affects the stability of the produced nanoparticles and their size. This observation offered an optimistic technique to produce StNPs via a green and eco-friendly process.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"187"},"PeriodicalIF":4.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12360022/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144874033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative approaches in bioremediation: the role of halophilic microorganisms in mitigating hydrocarbons, toxic metals, and microplastics in hypersaline environments.","authors":"Zeinab Rezaei, Mohammad Ali Amoozegar, Hamid Moghimi","doi":"10.1186/s12934-025-02817-7","DOIUrl":"10.1186/s12934-025-02817-7","url":null,"abstract":"<p><p>Hypersaline environments are ecologically, industrially, and scientifically important because they host unique extremophiles used in biotechnology, bioremediation, and enzyme production. These habitats are seriously threatened by three common contaminants: hydrocarbon pollutants, toxic metals, and microplastics. In particular, the remediation of hazardous substances under extreme conditions is challenging due to limited accessibility and bioavailability of pollutants, harsh physicochemical conditions, reduced microbial abundance and diversity, and instability of enzymes. Halophiles are extremophilic microorganisms that thrive in high-salt environments, exhibiting notable metabolic diversity and resilience, and play a critical role in overcoming these challenges. Their ability to degrade recalcitrant pollutants makes them valuable for bioremediation in contaminated hypersaline ecosystems. Advancements in engineering tools and synthetic biology have revolutionized halophile-based biotechnologies. Techniques like gene editing and recombinant DNA have facilitated the precise modification of halophiles, enabling them to efficiently target and degrade toxic compounds and significantly improve their bioremediation potential. Furthermore, with the rapid progress of omics approaches, identifying new halophilic microbes, their enzymes, and their metabolic pathways is now becoming possible. Despite these advances, challenges remain in optimizing genetically tractable strains, ensuring biosafety, and understanding microbial ecology for scalable, safe, and cost-effective applications. This review provides an overview of halophilic and halotolerant microorganisms, their habitat, and their unique adaptations to saline and hypersaline environments. Key pollutants threatening extreme environments, as well as the ability of halophiles to degrade them, are also discussed. Additionally, it highlights current challenges, including the introduction of engineered halophiles into natural ecosystems, scaling up bioprocesses, cost management, and regulatory concerns, and explains future perspectives to address these issues. Ultimately, it emphasizes the need for advanced research to fully harness the potential of halophiles in sustainable bioremediation.</p>","PeriodicalId":18582,"journal":{"name":"Microbial Cell Factories","volume":"24 1","pages":"184"},"PeriodicalIF":4.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12351994/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144847639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}